diff options
| author | Daniel Hellstrom <daniel@gaisler.com> | 2014-05-28 10:29:37 +0200 |
|---|---|---|
| committer | Daniel Hellstrom <daniel@gaisler.com> | 2014-11-19 16:29:58 +0100 |
| commit | 6dcd275550347d878c1f7c8ee39b87d56c9af742 (patch) | |
| tree | 5e292c7da8973b06ad511b384a120cd9a55db9ae | |
| parent | de4b74fd8478a569780e4565f864678f2014a6bc (diff) | |
SPARC: optimize window overflow trap entry
By using a optimized trap entry we can move instructions from
the window overflow function into the trap entry vector. By
using the saved locals instead of g1 we don't need to save
that register temporarily. Also spead out non store instructions
inbetween stores to use the write buffer better.
| -rw-r--r-- | c/src/lib/libbsp/sparc/shared/start/start.S | 11 | ||||
| -rw-r--r-- | c/src/lib/libcpu/sparc/reg_win/window.S | 24 |
2 files changed, 19 insertions, 16 deletions
diff --git a/c/src/lib/libbsp/sparc/shared/start/start.S b/c/src/lib/libbsp/sparc/shared/start/start.S index eb8e3c43a4..b7067b32bd 100644 --- a/c/src/lib/libbsp/sparc/shared/start/start.S +++ b/c/src/lib/libbsp/sparc/shared/start/start.S @@ -42,6 +42,15 @@ subcc %g1, 3, %g0; ! prepare for syscall 3 check /* + * Window Overflow optimized trap table entry + */ +#define WOTRAP(_vector, _handler) \ + sethi %hi(_handler), %l4; \ + jmp %l4+%lo(_handler); \ + save; \ + nop + +/* * Software trap. Treat as BAD_TRAP for the time being... */ @@ -72,7 +81,7 @@ SYM(trap_table): BAD_TRAP; ! 02 illegal instruction BAD_TRAP; ! 03 privileged instruction BAD_TRAP; ! 04 fp disabled - TRAP( 5, SYM(window_overflow_trap_handler) ); ! 05 window overflow + WOTRAP(5, SYM(window_overflow_trap_handler)); ! 05 window overflow TRAP( 6, SYM(window_underflow_trap_handler) );! 06 window underflow BAD_TRAP; ! 07 memory address not aligned BAD_TRAP; ! 08 fp exception diff --git a/c/src/lib/libcpu/sparc/reg_win/window.S b/c/src/lib/libcpu/sparc/reg_win/window.S index 453cc74ce4..535dc83105 100644 --- a/c/src/lib/libcpu/sparc/reg_win/window.S +++ b/c/src/lib/libcpu/sparc/reg_win/window.S @@ -29,9 +29,8 @@ * * On entry: * - * l0 = psr (from trap table) - * l1 = pc - * l2 = npc + * prev regwin l1 = pc + * prev regwin l2 = npc */ PUBLIC(window_overflow_trap_handler) @@ -51,28 +50,23 @@ SYM(window_overflow_trap_handler): * register will result in the local register set changing. */ - mov %wim, %l3 ! l3 = WIM - mov %g1, %l7 ! save g1 - srl %l3, 1, %g1 ! g1 = WIM >> 1 - sll %l3, SPARC_NUMBER_OF_REGISTER_WINDOWS-1 , %l4 - ! l4 = WIM << (Number Windows - 1) - or %l4, %g1, %g1 ! g1 = (WIM >> 1) | - ! (WIM << (Number Windows - 1)) - - save ! Get into window to be saved. - mov %g1, %wim ! load new WIM std %l0, [%sp + 0x00] ! save local register set std %l2, [%sp + 0x08] + mov %wim, %l3 + sll %l3, SPARC_NUMBER_OF_REGISTER_WINDOWS-1 , %l2 + ! l2 = WIM << (Number Windows - 1) std %l4, [%sp + 0x10] std %l6, [%sp + 0x18] + srl %l3, 1, %l3 ! l3 = WIM >> 1 + wr %l3, %l2, %wim ! WIM = (WIM >> 1) ^ + ! (WIM << (Number Windows - 1)) std %i0, [%sp + 0x20] ! save input register set std %i2, [%sp + 0x28] std %i4, [%sp + 0x30] std %i6, [%sp + 0x38] restore ! Go back to trap window. - mov %l7, %g1 ! restore g1 jmp %l1 ! Re-execute save. - rett %l2 + rett %l2 /* * Window underflow trap handler. |